Collapsible tube



March 1946- EBOGOSLOWSKY COLLAPSIBLE TUBE 2 Sheets-Sheet Original Filed Jan. 25, 1943 INVENTOR March 19, 1946. B, BO OSLOWSKY 2,396,635

COLLAPS IBLE TUBE Original Filed Jan. 23, 1945 2 Sheets-Sheet 2 Patented Mar. 19, 1946 BIBLE E Boris Bogoslo, Iackson Heights, N. Y.

original application January as, 1943, Serial No.

473,322. Divided and this application Decemher i, 1943, Serial No; 512,457

2 Claims.

This invention relates to collapsible tubes and to methods for the manufacture thereof, and constitutes modifications of or improvements on the collapsible tubes and methods for the manufacture thereof disclosed in my copending application Serial No. 421,624, filed December 4, 1941.

This application is a division of my copending application Serial No. 473,322, filed January 23, 1943.

It is an object of the invention to provide a collapsible tube made of materials in sheet or film form as hereinafter described, as a substitute for the extruded metal collapsible tubes now in common use.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawings, in which,

Figure 1 is a front elevation, partly in section, showing the mandrels in position to begin the forming operation.

Figure 2 is a similar view showing a later stage in the forming operation.

Figures 3, i and 5 are similar views showing an alternative method of procedure.

Figure 6 is a front elevation-showing the tubes on completion of the forming operation.

Figure 7 is a sectional view on the line ll of Figure 6.

Figures 8 and 9 are sectional views showing the method of applying heat and pressure to re-form and compress the shoulder and neck.

Figure 10 is an enlarged detail sectional view of the same.

Figure 11 is a front elevation, partly in section of a finished tube.

As materials for use in the manufacture of collapsible tubes according to my invention. I may use many of the plastic films or sheets now available in the commercial market, as for example, the various cellulose base films such as the commercial product "Cellophane, or resin base films such as the commercial product Vinylite, or rubber base films such as the commercial product Pliofllm." Or I may use paper or other sheet materials fo some p rposes. The selection of a suitable material will depend entirely on the nature of the contents to be packaged in the tube formed therefrom. but I prefer to use material which is thermo-plastic or heat sealing for reasons which will be apparent hereinafter. If paper or other sheet materials which are not thermoplastic or heat sealing are used, such materials should preferably be coated or laminated with thermo-plastic or heat sealing materials.

In practicing the invention hereinafter described I prefer to start with the sheet or film 5 material in the form of cylindrical tubular blanks cut to the desired length. It is possible to obtain some of the above-named plastic films or sheets in the form of seamless tubing, and I may employ such tubing in carrying out my invention. However, it is cheaper and for most purposes more satisfactory to form cylindrical tubular blanks from flat sheet or strip materiaLeither by rolling the same and sealing the formed tube along a1ongitudinal seam, or by spiral winding and sealing the overlapping spiral edges. Suitable machinery for making such tubular blanks is obtainable and the formation of such tubula blanks forms no part of the present invention.

Such tubular blanks are preferably formed of more than a single ply of material, and may, if desired, be reinforced or stiffened by interposing a sheet of stiflening material of paper, metal foil. o the like between successive plies. If the material of the tubular blank is of a transparent nature, a suitable label printed on the .stifienins material will be visible through the tubular blank and serve the same purposes as the label now printed on the outside surface of metal collapsible tubes. Such stiffening material should preferably be of a length less than the length of the tubular blank, and at the upper end should not extend beyond the point at which the shoulder is to be formed ashereinafter described, for the formation of the shoulder can be accomplished to better advantage with unstifiened material. The purpose of the stifiening material is merely to stiffen the dylindrical wall of the finished tube.

Referring to Figures 1 and 2, according to the present invention I place such a tubular blank 8 of the selected material on a pair of spaced cylindrical mandrels 2 and 3, said. mandrels being aligned axially by a co-axial spindle d extending into passages 5 and 6 through said mandrels. The said spindle should fit snugly in said passages, but at least one ofsaid-mandrels, and preferably both of said mandrels, should be permitted to rotate on said spindle and to slide longitudinally thereon.

After placing the blank on the mandrels as shown in Figure'l, with the opposed ends of the mandrels spaced apart a predetermined distance, as shown, the ends of the blank are clamped to the respective. mandrels by any suitable means,v and the mandrels are rotated relative to one an- 55 other, i. e. one mandrel is rotated in clockwise directionandtheothermandrelisrotatedin coimter-clockwise direction as indicated in Figure 2, or alternatively, one ofthe mandrels may be held stationary and the other mandrel rotated relatively thereto. Such relative rotation twists the unsupported portion of the tubular blank lying between the mandrels, causing the same to pucker inwardly toward the spindle. the mandrelsbeingallowedtomoveaxiallytowardeach other as the twisting movement continues.

The twisting movement causes the unsupported material to form itself into a multiplicity of small spiral folds. and continued twisting movement causes the spirally folded materialto wind itself mt]! aroundthe'spindlel (Figure2) andtolie tightlyagainsttheoppoeedendsurfacesland I of the mandrels. which in the preferred embodiment illustrated, are of conical form. Thus, as

rshowninriguresdand'bthespiralfoldsbcain at the periphery of one mandrel. for example, the mandrel I, extend inwardly along the conical surfaces I with the fold linesextending in a direction tangent to the neck. then extend spirally around the spindle to the conical sm'iace I, and then extend outwardly along the conical surface I to the periphery of the other mandrel I.

The tubular layer of material which is spirallywound on the spindle, and which providm the material for. the formation of the neck of the finished tube as hereinafter explained, is, due to such spiral winding, of a thickness greater than the wall thickness of the tubular blank, and the folded material ll, II which abuts the end surfaces of each of the mandrels, and which constitutes the shoulder of the finished tube, increases in thickness from the periphery of the blank to the point of juncture with the layer I.

An alternative method of proceeding is shown lnFlgllres 3,4 and 5. Inthisuseatubularblank i is placed on the mandrels as before, but the mandrels, as shown in Figure 3, are more closely spaced than in Figure 1. Again, the mandrels are rotated relative to one another, but for convenience in the following description. it will be assumed that the lower mandrel 4 is held stationary and that the upper mandrel 3 is rotated relative thereto. In this case the tubular blank is clamped tightly to one mandrel, say the lower mandrel, but is not clamped tightly to the other mandrel, being merely held in such manner as to cause the upper end of the blank torotate with the mandrel, while allowing the blank to creep longitudinally of the mandrel as hereinafter described. This may be done, for example, by using rollers (not shown) as the blank holding means.

After placing the blank on the mandrels, the upper mandrel is rotated to twist the unsupported portion of the blank to cause the same to pucker inwardly as shown in Figure 4, the upper mandrel being allowed to move toward the lower mandrel during this portion of the operation. On arrivin at the position shown in Figure 4, and while continuing the rotation of the upper mandrel, the upper mandrel is backed away from the lower mandrel, while allowing the blank to creep longitudinallv of the upper mandrel. In this manner the material is 88 -111 twisted ti htly around the spindle 4 as shown in Figure 5, and by controlling the rate at which the mandrel is backed away relative to the rate of rotation thereof, the thickness of the spirally wound layer I may be controlled.andincaseswhereathicker layermaybe desirable, it may be readily obtained in this manner Except for such variation in thickness, the re- 76 It will be understood that the invention suit of both methods of procedure is identical. and asillustratedinl'lsurc 6,consistsintheiormation of two embryo tubes in one operation, each consisting of a tubular body portion. a shoulder of spirally folded material, and an elongated neck of tigh y twisted spirally wound materiahall of said parts being formed integrally from a single tubular blank. .The next step, therefore, is to sever the two tubes by cutting through the neck portion near the middle thereof in any suitable mannenashythe knife ii.

The elongated common spindle 4 is now re moved from the mandrels. and a shorter pindle i2 is inserted in each mandrel for purposes hereinafter described. A mandrel, as for example the mandrel 2, carrying an embryo tube is then in. sertedinapressha aopposed plates "and il, one of said plateecarrying a die I! having a cavity ll therein. The said cavity has slightly taparing walls I1 and has a conical surface it adapted to cooperate with the conical end surface of the mandrel to form the'shoulder of the tube. At the bottom of the cavity It is a smaller cavity ll adapted to receive the neck of the tube.

. substantial, 1. e. in the finished tube the wall thick-.

said cavity having a threaded wall adapted to form a thread on the neck of the finished tube. There is also a passage 20 through the-die into which the spindle I2 is fitted. The die it is heated in anv suitable manner. as by a suitable electrical heating element or by steam, with provision for temperature control at the required level fo seal ing the selected material.

when the mandrel is inserted shown in Figure 8, the outside diameter of the neck is less than the inside diameter of the threaded cavity it, but the length of the neck is greater than the. depth of the cavity. Thus, when pressure is applied, as shown in Figure 9, the materlal in the neck is reformed under the influence of heat and pressure, and is compressed to provide a shortened, but thickened, threaded neck as shown'in Figures 9 and 11. At the same time. the folds of the shoulder are subjected to heat and pressure, the spindle i2 serving, however, as a limit stop to prevent application of excessive pressure thereto. In order to provide adequate strength. the-thickening of the neck should be ness of the neck should be at least twice the wall thickness of the tubular body portion of the tube. The application of heat and pressure, of course, not only reforms the neck, but seals the overlapping folds of the neck and shoulder, and in eflect, welds them together to provide increased strength and stiffness in the finished tube. Particularly the neck assumes a strength and rigidity appreaching that of metals such as tin. After the pressure is released, the tube is removed from the die by unscrewing the same, this being necessary because of the interengaging threads of thetubeanddiecavity.

The resulting tube is admirably suited for use as a collapsible tube, for the cylindrical wall is thin and flexible, while the shoulder, due to the folds which provide increasing thickness from the periphery to the juncture with the neck, and

stantial strength and rigidity, and when provided with a thread as illustrated, is adapted-to receive the ordinary threaded cap as ordinarily used-asa closure for metal collapsible tubes.

in the press as be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention: 1. A collapsible tube of sheet material, comprising, a flexible cylindrical tubular portion, and

an integral shoulder and neck, all formed from a single tubular blank, said shoulder extending inwardly from said tubular portion and consisting of a multiplicity of small folds, said neck being tubular and consisting of twisted folds forming continuations of the folds of said shoulder and terminating at the end of said neck, said twisted folds of the neck being compressed to form a shortened, thickened tubular wall of substantial strength and rigidity.

2. A collapsible tube of sheet material, comprising, a flexible cylindrical tubular portion, and I an integral shoulder'and neck, all formed from BORIS BOGOSLOWSKY. 

